Metal extrusion press and method of operation



Feb. 8, 1938.- E. w. McKNl'GHT l 107596 u METAL EXTRUSION PRESS AN)METHOD OF OPERATION Filed Deo. 19, 1935 4 sheets-sheet 1 i 1 4 V ffl? ilN l) 54 vif ffy

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Feb. 8, 1938. 'E. W. MacKNlGHT 2,107,896

METAL EXTRUSION PRESS AND METHOD OF OPERATION Filed`Dec. 19, 1953 '4Sheets-Sheet 2 g BY D.

E ATTORNEYS.

. 19, 1935 4 Sheets-Sheet 3 Wm f 5 l .f i f Z 4. 7 a. R n S 5 5 5 f 7 i4. I a 0 0.@ f w y M y 7 f MM m l E c R @a I H i a m 00%00 5 K nu W I lHf l W. ...5, m 2 d ,a |I j f I B 7 5 5 L1 I J d 0 l .v 4l. 4J a. m W1|: Il 4| L una. m5 7 f W i rmx E. W. Maf/KNIGHT Fled Dec Feb. 8, 1938.

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METAL EXTRUSION PRESS AND METHODOF OPERATION Filed Deo. 19, 193s 4sheets-sheet 4 wwwaaaeeam IN V EN TOR.

Patented Feb. 8, 1938 METAL EXTRUSION PRESS AND METHOD F OPERATION EdgarW. MacKnight, Bayonne, N. J., assignor to General Cable Corporation, NewYork, N. Y., a corporation of New Jersey Application December 19, 1933,Serial No. 703,057

22 Claims.

This invention relates to metal extrusion presses and the method ofoperating such presses. More particularly the invention is concernedwith presses for extruding metal sheaths on electrical cables.Ordinarily, cable sheaths are made of lead or an alloy of lead. It is anobject of this invention to provide improved apparatus for extrudingmetal, and also to provide an improved method of operating suchapparatus in which the a press for extrudlng cable sheaths, and of the-lassociated metal pot;

Fig. 2 is a top plan view of the bracket |25 shown in Fig. 1;

Fig. 3 is an enlarged vertical section through the upper end of thepress cylinder, the lower end of the press ram and the stuiling boxconnecting these two members;

Fig. 4 is a section substantially on the line 4 4 of Fig. 3; 1

Fig. 5 isvan enlarged vertical section through the upper end of thepress ram and the canopy of the press;

Fig. 6 is an enlarged vertical section through a portion of the metalmelting pot, showing the metal measuringand pumping device;

Fig. 7 is a section substantially on the line 1- 1 ofFig.6;

Fig. 8 is a section substantially on the line 8 8 of Fig. 6;

Fig. 9 is a vertical section through a valve which, in some cases, maybe substituted for the metal measuring and pumping device shown `in Fig.6;

Fig. l0 is a somewhat diagrammatic showing of apparatus used, forexample, with the valve shown in Fig. 9 for measuring and indicatingcontinuously' the amount of metal extruded from the press in anextrusion operation, and also the amountof metal entering the pressduring acharging operation; and

Fig. 11 is a view of the indicator dial substantially 0n the line lI--Ilof Fig. 10. v

In sheathing electrical cables with metal there are two types ofvertical presses in general use.

In one of these the press cylinder is stationary press ram is stationaryand the press cylinder moves. The present invention is most easilyadapted for and is illustrated herein with reference to a press in whichthe ram is stationary.

The actual extrusion of metal is not continuous in either type of pressfor the reason that it is necessary to separate the ram and the cylinderand recharge the cylinderrwith metal when a majority of the originalcharge lof metal has been extruded from the cylinder. In recharging, thecylinder is lled with molten metal, and then it is necessary to waituntil the metal cools sufficiently to solidify before the extrusionoperation can be continued.

Heretofore it has been the common practice in charging a press cylinderto separate th'e cylinder and the ram, and then to ll the cylinder withmolten metal from a nearby melting pot by opening a valve at the bottomof the pot and permitting metal to flow down an inclined trough, thelower ;end of which has been moved overthe open end of the presscylinder. When the cylinder has been filled with molten metal the valveat the bottom of the pot is closed, and an effort is made to remove thedross on the top surface of the metal in the cylinder either byflotation or by skimming. The ram is moved downwardly to seal the chargeand then it is necessary to suspend operations until the molten metalhas solidied. After solidication of the charge the extrusion operationmay be continued.

In operating presses as described above, impurities are accumulated byor formed in 4the molten metal, and also on the exposed surface of thehot metal slug remaining in the cylinder, and on the thin layers of hotmetal on the surfaces of the cylinder and ram. Exposure of the moltenmetal to the air as it issues from the melting pot and flows through thetrough to the press cylinder is accompanied by oxidation of the metal.This oxidation results in the formation of dross which is carried intothe press cylinder. The upper surface of the slug left in the cylinderat the completion of an extrusion operation also begins to oxidize assoon as the ram leaves it on its up-travel. Likewise the thin lm ofmetal on the inner surface of the cylinder andthe end of the ramoxidizesl and finds its Way into the charge. This oxidized film tends toprevent perfect welding of the new charge, and While a portion of theoxide may float to the top and be skimmed oif, apart of it will remainin the charge. This oxide may reduce the strength of the bond in thecable sheath. Furthermore,v some metal may cling to the trough at thecompletion of a chargmg operation'. such metal will oxidize in the airand build up into large particle sizes which will be carried into thecylinder with the molten metal during the next charging operation.

In charging a press in the manner just described the metal which runsinto the cylinder strikes the relatively cold wall of the cylinder andfreezes in an irregular lump. The surface of this lump lms overinstantly and is continuously spattered with more hot metal, forming alarger lump containing oxide and gas bubbles which eventually mustappear in the cable sheath. These entrapped air or gas pockets arecompressed to very small size during the extrusion operation, and expandagain after passing out of the die. If the pocket is near the surface ofthe sheath it will explode outward and perhaps may be discovered andrepaired, but it is just as likely that the pocket will occur adjacentthe inner surface of the sheath and burst inwardly, to the detriment ofthe cable insulation, as well as the sheath. Also there is some dangeroi carrying metallic oxide and other dirt from the melting pot andtrough into the cylinder.

According to the present invention a commercially practicable method andapparatus is provided for extruding cable sheaths, in which oxidatlon ofthe slug remaining in the cylinder prior to a charging operation isprevented, and in Which molten metal passes from the melting pot to thepress cylinder without exposure to the air or any other gas at any pointduring its movement. cylinder and lower end of the ram, b'oth of whichcome in contact with the metal, are not exposed to the air or other gas,and are therefore free Afrom oxides. y

Referring first to Fig. 1, the vertical columns 2 l', four in number,support near their upper ends the press canopy 22, from which depends'the press ram 23. The ram 23 enters the upper end of the presscylinder24. Secured on the upper end of the cylinder 24, as' by means ofthe screws v25, is a stuiling box 26 which surrounds the ram.

This stuilng box comprises a seal preventing `access of air into thecylinder, while permitting relative movement between the ram and thecylinder.

In the illustrative embodiment the cylinder 24 rests on a layer of heatinsulation 21, on top of a iiow plate 28, which in turn is supported onthe die block 29. However, the cylinder may rest directly on the dieblock 29, either or both the insulation and the flow plate beingomitted` The die block 2 9 has a horizontal die opening 38 through whichthe cable passes during the sheathing operation. The die block rests on'the upper end of the hydraulic press plunger 3| which may be moved upand down under the action of hydraulic press mechanism not shown here.

'I'he construction of the vlower end of the press ram 23 and of thestuffing box 26 will be better understood by referring to Fig. 3. Thestung box comprises the ring-like casting 26 having spaced around itsperiphery a plurality of holes to receive the screws 25 by means ofwhich it is secured on the upper end of the cylinder 24. An air-tightjoint between the top'surface of the cylinder end and the stufiing boxis secured by means of the packing ring 32, for example asbestos,positioned in an annular groove on the lower face of the casting 26.When the screws and an air-tight joint is established.

Furthermore the inner surfaces of the The central opening through thecasting 26 conveniently is large enough to permit moving it over thelower end of the raml 23. As will appear hereinafter, the lower end ofthe ram 23 preferably is slightly larger in diameter than the main -bodyof the ram. The central opening through the casting 26 has al shouldersupporting the packing gland ring 33. The gland ring 33 has a sliding twith the main body of the ram and conveniently may be formed in twopieces to permit assembly about the ram in the stuing box. Desirably thelower edge of the gland ring 33 is inclined upwardly away from the ramso that when the press cylinder is moving away from the ram any metalwhich might have escaped from thecylinder around the lower end Vof theram will be shaved oi of the ram, thereby protecting the stuing boxpackings.

Surrounding the ram and resting on the gland ring 33 are annularpackings 34, for example asbestos. Over the packings 34 is the gland 35,also conveniently formed in two'pleces to provide a sliding t with theram. The gland 35 is forced downwardly to compress the packings 34between the stuffing box 26 and the ram 23 by means of the ring 36 andthe screws 31.

, The arrangement of the stung box just described provides an air-tightjoint between the upper end of the press cylinder and the press ram, butdoes not interfere with free movement between the cylinder and ram inthe normal operation of the press.

Means are provided for evacuating the space between the press cylinderandl the press ram under the stuffing box. As shown in the drawings, apipe 38 is secured in an opening through the wall of the casting 26, andthis pipe is connected to evacuating apparatus, for example a pump, notshown. By maintaining a high vacuum within the press cylinder under theram, oxidation of the slug of metal remaining in the cylinder during acharging operation, and of the molten metal with which the cylinder ischarged, are eliminated. Furthermore, the formation of gas pockets orbubbles in the charge is prevented.

The ram 23 has a longitudinally extending central opening 4| which isenlarged for a short distance at the lower end of the ram as shown at 42in Fig. 3. This enlarged opening 42 is screwthreaded to receive thethreaded hub 43 of the end. block 44 for the ram. This end block has aclose sliding t with the bore of the cylinder, and conveniently Visprovided with Spanner wrench holes 45 to facilitate securing it intoposition.

The end block 44 has a shoulder central opening, the lower portion ofthis opening flaring outwardly, as shown at 46, at an angle ofpreferably about 45 degrees to provide a. valve seat.

Mounted in the upper portion of the end block 44, and supported on theshoulder, is a tubular metal member 41. The member 41 preferably isflanged at its lower end, and this flange 48 may be separated from theshoulder in the block 44 by means of thermal insulation 49. Thisinsulation 49 conveniently is placed under compression, as by means ofthe tube 50 loosely surrounding the member 41 and bearing on the outeredge of the flange 48. vThe tube' 50 conveniently is pressed downward bymeans of a ring 5I and the screws 52 passing therethrough and enteringthe hub 43. l

The wall of the member 41 desirably is made fairly thin to insurecorrect heating, as will appear more fully hereinafter. For this reasonit may be desirable to reinforce the wall as by means of the surroundingcircumferential rings or bands 53. y

The lower portion of the member 41 adjacent its 'anged end is somewhatreduced in diameter as compared to the main body of the member. Looselymounted in the opening through the end block M is a valve stem l whoseupper end desirably is round or pointed, and provided with a spider headhaving arms 55 which loosely enthe valve sea-t 46, thereby closing thepassageway y between the press cylinder and the member 41, andpreventing ow of metal outwardly from the cylinder. When the valve stemmoves downwardly thisl passagewaywill be open, permitting ilow of moltenmetal into the cylinder.

Preferably, the valve 56 extends downwardly beyond the lower face of theend block 44 somewhat in the manner shown in Fig. 3. This extension ofthe valve into the press cylinder constituixes a means whereby theoperation of the valve may be controlled automatically by the charge ofmetal in the cylinder in response to relative movement between thecylinder and the ram. While metal is being extruded from the press thevalve is forced upwardly in the valve seat by the pressure in thecylinder and becomes'rmly embedded in the upper end of the charge ofmetal in the cylinder. When movement between the cylinder and the ram isreversed for the purpose of recharging the cylinder with'molten metalthe grip of the metal onthe lower end of the valve 56 is sumcient topull the valve and valve stem downwardly, thereby opening the valvevbefore and ram move toward each other the valve will which desirablytightly engages the inner wall of the member I1. This plug 6I has adownwardly tapered central opening which receives the tapered lower endof a pipe 62 extending upwardly through the longitudinal opening Il inthe ram 2l. p

Referring now to Bg. 5, the'pipe 62 desirably is supported againstbuckling in its passage upwardly through the press ram and canopy.Conveniently this-support takes, the formof an in- Y sulating bushing 63surrounding the pipe where the pipe emerges from the ram into thevertical opening 65 in the canopy. The insulating bushing 63 ts looselyabout the pipe 62 to permit evacuation of the annular space in the ramthrough the upper opening in the canopy. The insulating bushing 63 maybe held in place by means of a metal ring 64.

The vertical opening 65 in the press canopy is closed at its upper endas by means of a metal plate 66 secured to the canopy with screws 61.Between the canopy and the plate 66 is a compression packing 68 toinsure an air-tight joint. The pipe 62 passes outwardly of the canopythrough a stuing box an enlarged central opening in the plate 66.

Secured in this opening in the plate 66 is a cup member 69 containing aninsulating packing surrounding the pipe 62. Convenientlythis packing maycomprise asbestos board bushings 10 between which is a layer 1i ofasbestos packing.'

Thev packing is maintained under compression, thereby sealing thepassage between the pipe 62 and the cup 69, as by means of a plate 12loosely surrounding the pipe and forced downwardly against the upperbushing 1li by the screws 13.

It will be apparent from the foregoing description that by means of theIstumng box the joint between the pipe 62 and the canopy 22 may be madeairtight, and that the pipe 62 may be inserted or removed merely byloosening the stuffing box connection at the top of the canopy.

A tight connection between the lower end of the pipe 62 and the plug 6lis maintained by pressing the pipe downwardly so that its lower endengages the aperture in the plug 6i with a. tight wedging action.Conveniently, this downward pressure on the pipe 62 may be maintained inthe manner illustrated in the upper part of Fig. 5.

Clamped about the pipe 62 a. short ways above the plate 12 are two clips14. Bearing downwardly on the upper of these clips, but separatedtherefrom by a block 15 of electrical insulating material, is one end ofthe lever 16. The other end of the lever 16 rests on a support 11extending upwardly from the canopy 22. Intermediate its ends the lever16 is guided vertically by sliding along the pin 18 extending upwardlyfrom the canopy.

The lever conveniently is forced downwardly by means of a helical spring19 surrounding the upper end of the pin 18 and compressed between the.lever and a washer and nut on the upper end of the pin. With such anarrangement a tight connection is assured between the lower end of thepipe 62 and the plug 6I.

Also secured to the pipe 62 by means of the clips 1I is an electricallead 8| to permit connection of 'the pipe in an electrical circuit forheating purposes, as will be described more fully hereinafter.

The plate 66 secured on top of the canopy also has an opening into theannular space surrounding the pipe 62 within the canopy and ram of thepress. Secured in this opening is apipe 82 which is connected to avacuum pump, not'shown. By means of this connection 62 the annular spacewithin the canopy and ram around the pipe 62 may be evacuated.

Above the point where the clips 1l are attached the pipe 62 is bent fromthe vertical so that it illustrative embodiment, the pipe is to beheated electrically to insure free passage of molten metal therethroughfrom the container 81 to the press cylinder, the pipe desirably iscovered throughout its length between the press and the container1 witha thick wall 83 of heat insulating material.

Secured to the pipe 62 over the upper end of the melting pot, as bymeans of a clip it, is an electrical lead 85. Over the melting pot thepipe 62 is bent downwardly and passes through a stumng box 3B in theupper end of the melting pot t1 into the pot. Conveniently this stungbox 8S may be simiLr to the stufng box surrounding the pipe 62 where itemerges from the press canopy.

The pipe 62 desirably is one unbroken length extending from the pointwhere it discharges into the press cylinder to the point where it issupplied with molten metal in the container 81. Where a single length ofpipe is used there is much less danger of a leak permitting access ofair to the molten metal in its passage through the pipe. Also there isless danger of the pipe becoming clogged, since uniform heating of thepipe is facilitated and Acan be more accurately controlled than would bethe case if several lengths of pipe were used with elbows andcouplings.' It is necessary that the pipe 52 be heated above the meltingpoint of the metal which is to be extruded so that in passing from themelting pot to the press the metal will not freeze and block the pipe.

It will be noted that a portion of 'the pipe is surrounded by the pressram and canopy, that another portion of the pipe is exposed to theatmosphere except for the insulation 83, and that a third portion of thepipe extends into the cen'- tainer of molten metal. These severalsections of the pipe will need different amounts of heat to furnish asubstantially uniform temperature throughout the length of the pipe.Conveniently, thev pipe is heated by passing electric currentlongitudinally therethrough, and suitable connections are showndiagrammatically in Fig. 1.

In this illustrative embodiment the pipe is divided electrically intothree sections. A source of electric current, for example a transformer9|, is connected by means of an electrical conductor 92 to the frame ofthe lead press, and-by means of a conductor 93 to the electrical lead 8lsecured to the pipe 62 adjacent the point where it emerges from thepress canopy. A second source of electric power, for example thetransformer 94, is connected by means of a conductor 95 tothe electricallead 8| on the pipe 62, and by means of a conductor 96 to the electricallead 85 on the pipe 62. A third source of electrical power,A for cxamplethe transformer 91, is connected by means of a conductor 98 to theelectrical lead 815 on the pipe 62, and by means of a conductor 99 tothe metal melting pot 81. By regulating the currents flowing througheach of these three sections of pipe it is possible to obtain asubstantially uniform temperature throughout the length of the pipe.

One means for segregating a charge of molten metal in the pot 81 and forforcing this molten metal through the pipe 62 into the press cylinder lsshown in section in Fig. 6. The pipe B2, passing downwardly through thestuing box 86 in the melting pot 81 terminates within the interiorlyshouldered pipe with a close sliding t. VThe pipe |0| is secured at itslower end in the pump cylinder head |02. The pipe |0| connects by meansof a passage |03 through the cylinder head with the interior of the pumpcylinder |04.

The interior of the pump cylinder |06 also is connected through thepassageway in thecylinder head, and the Valve |06 to the interior of themelting pot 91. The valve 05 is opened and closed by means of the valvestem |01 extending upwardly through a stui'ng box |08 in the top of themelting pot 3l.I The Valve 90S has a horizontal opening therethrough, sothat when the valve is turned to one position this opening registerswith the passageway |05, and when the Valve is rotated 90 degrees thisopening in the valve is crossways of the passageway |05, preventing owof metal therethrough. The valve operating mechanism will be describedmore fully hereinafter.

The pump cylinder head |02 desirably is positioned within the meltingpot 81 so that in the normal course of operation molten metal alwayswill be withdrawn from a point at some distance from the walls of thepot 81 as well as at some distance below the level of the metal. Thelevel of metal in the pot will vary, of course, as molten metal iswithdrawn and as new metal is added. Desirably the intake which suppliesmetal through the pipe 62 to the press is located far enough down in thepot so that any dross formed on the metal surface will not be carriedthrough the pipe t2 into the press. Desirably, the intake for the moltenmetal is located some slight distance above the bottom and spaced fromthe Walls of the p ot to prevent transfer to the press of any impuritieswhich may have accumulated or formed on the /bottom or walls ofthe pot.Y

Mounted within the pump cylinder IM is the piston |09, desirably fittedwith piston rings H0.

Adjacent its upper end the cylinder |06 is provided with a plurality ofports to permit entrance and exit of metal back of the piston as thepiston moves up and down in the pump cylinder. The cylinder convenientlyis secured at `its upper end to the top of the pot 81, for example bymeans of a cylindrical member ll2'rmly secured in an opening in the topof the'pot.

Extending upwardly from the piston |09 to which it is secured is thepiston rod 3. The piston rod ||3 passes through the cylinder Mld, astung box H4 in the lower end of the member I2, and continues upwardlybeyond the top of the melting pot. Formed on or secured to the upper endof the piston rod ||3 is a gear rack H5. The piston andpiston rod aremovable vertically, and this movement is controlled by means of a pinionI6 engaging the rack I |5.

The pinion H6 is rigidly secured on the shaft I1. One end of the shaftI1 is rotatably mounted in bearings on the upper end of a housing ||8rising from the top of the melting pot 81. Referring now to Fig. l, theother end of the shaft is rotatably mounted in a bearing, not shown, onthe press canopy 22. Rigidly secured on the shaft ||1 adjacent the leadpress is a sprocket ||9. Engaging the sprocket ||9 is a powertransmission chain which passes downwardly and around a sprocket |2|rotatably mounted near the bottom of the columns 2|.

The ends of the sprocket chain passing around the sprockets I9 and |20are connected by means of a screwthreaded link |22. Spaced apart on thelink |22 are two sets of adjustable lock nuts |23 and |24. Engaging thelink |22 between the two sets of lock nuts is the forked end of abracket which is secured on the upper end of the hydraulic press plunger3| so as to move up and down with the plunger.

It will be apparent that as the plunger 3| moves4 up and down thebracket |25 will cause the sprocket vchain |20 to move, thereby rotatingthe shaft ||1. As the press cylinder 24 is moved upwardly during anextrusion operation the shaft ||1 will be rotated so as to raise thepiston |09, thereby filling the pump cylinder- |04 with molten metalfrom the melting pot. When the press cylinder 24 reverses direction andmoves down' Wardly, the piston |09 will move in the opposite directionto force the molten metal from the pump cylinder |04 through the pipe62into the press cylinder 24.

By spacing the sets of lock nuts |23 and |24 apart on the connectinglink |22, a slight lost motion may be introduced so that molten metal isnot forced from the pump into the press cylinder until the valve in thelower end of the press ram is fully opened. 'lhis lost motion also makesit possible to vmaintain any desired clearance, for example an inch,between the end of the ram and the surface of the molten metal duringthe charging operation.

One suitable mechanism for operating the valve |06 controlling the flowof molten metal into the pump cylinder |04 is shown in Figs. 6, 'I and8. On the outer end of the shaft i l1, spaced a short distance apart,are rigidly secured two ratchet wheels |3| and |32. Mounted on the shafti |1 hetween these ratchet wheels and free to turn about the shaft is alever |33 having at its outer end a weight |34. Rotation of the lever|33 about the shaft ||1 is limited by means of the ears |35 and |36,which engage a stop |31 in the top of the housing I8 as the lever turnsto the right or left as viewed in Figs. 7 and 8.

Pivotally secured on opposite sides of the lever |33 are the pawls |30and |39 which engage, respectively, the ratchet wheels i3| and |30.Referring to Fig. 8, rotation of the shaft iii to the right when thelever |33 isfturned to the left, as shown in dotted lines, causes theratchet wheel |3 I, engaging the pawl |38 to turn the lever to theright. When the lever is carried past the vertical position the weight|34 on its outer end causes the lever to continue its turning movementto the right at a more rapid rate until the ear 36 engages the stop |31.vDuring this more rapid turning movement the pawl |3615 lifted out ofenu gagement with the paw] wheel |39 and is held out of engagement bythe arm |00 xed on the top of the housing i l0 which engages the outerend of the pawl.

' is held out of engagement by means of the arm |4| secured on the topof the housing H0.

4Thus it will be seen that rotation *of the shaft. 'I I1 in eitherdirection approximately one eighth of a turn shifts the lever |33 fromone limit of its range of movement to the other limit.

Also mounted on the shaft ||1 adjacent its end is a sheave |42 which issecured to the lever |33 by means of the connection |43 so that thesheave will turn about the shaft ||1 with the lever |33. Passing aroundthe sheave |42 is lthe wire or cable |44. The wire |44 passesdownwardly, changes directionA about the sheave |45 rotatably mounted onthe housing ||0. and then around the sheave |46 rigidly secured on theupper end of the valve stem |01. The valve stem. |01 is presseddownwardly to force the valve |06 into its seat as by means of a helicalspring |41 surrounding the valve stem |01 and compressed between thervalve stem bearing |48 and a collar |49 secured on the valve stem |01.

From the foregoing description it will be apparent that upon rotation ofthe shaft ||1 approxiy. mately one-eighth of a turnin one direction thevalve |06 will be opened, and that upon rotation ofthe shaft ||1approximately one-eighth of a turn in the opposite direction the valve|06 will be closed. During the extrusion operation the valve |00is openso that molten metal will be drawn into the pump cylinder |04 by meansof the piston |09, and as the press cylinder moves away from the pressram the valve |06 is closed so that the molten metal segregated in thepump cylinder is forced by the piston through the pipe Desirably thediameter of the pump cylinder and the stroke of the pump piston are suchthat as metal is being extruded from the press an equivalent quantity ofmolten metal is being segregated within the pump cylinder. For example,the pump cylinder might have the same internal diameter as the presscylinder, and the pump piston might move through the same distance andat the same speed as the press cylinder. Under such conditions the pumpalways would contain the correctv amount of molten metal for rechargingthe press, regardless of the amount oi metal whichmay have been extrudedfrom the press.

During the extruding operation a specic quan tity of molten metalequivalent to the quantity of metal extruded is being segregated withina separate container, in this instance the pump. When the extrusionoperation has been completed the press cylinder recedes from the pressram, and as it does so, the press cylinder is progressively charged withthis metal which has been segregated in the separate container. Bysuitable adjustment of the lost motion connection between the presscylinder and the transmission chain which actuates the metal pump the owo molten metal into the press may be delayed to maintain a clearancebetween the level of the A62 into the press cylinder. f

metal and the end of the ram. When the chargn ing of the press cylinderhas 4been completed and the metal has cooled suiilciently to permit ex-ntrusion thereof the pump. in the melting pot segregates the metal whichwill be required for the next charging of the press. This operation ofthe pump is fully automatic in response to relative movement between the-press vcylinder' and ram. Desirably the space within the press cylinderunder the stuiling box around the ram is evacuated, throughout theoperation, and air or other gases do not have access to the metal at anytime during the charging operation.

Splashing of the metal and the formation oi' irregular lumps in thepress cylinder during the charging operation are greatly reduced by rnof the point and direction of discharge of the molten metal into thecylinder, as well as by reason oi' the fact that the molten metal fallsthrough a much shorter distance in the cylinder. Since the cylinder isevacuated, the formation of gas bubbles or pockets is eliminated.

Ifthe distance which the molten metal must rise in passingfrom themelting pot through the 'pipe 6 2 to the press cylinder u not. toogreat.

the atmospheric pressure maybe utilized to force molten metal from themelting pot into the evacuated press cylinder. In that case the pumpdisclosed in Fig. 6 and the operating mechanism therefor disclosed inFigs. 6, 7 and 8 may be omitted, and a valved inlet alone is requiredfor the end of the pipe 62 within the container 67.

Such a valved inlet is shown in Fig. 9. Anr

opening in the top of the melting pot 87 is closed with a plate |5|,conveniently held in' place by means of screws |52. An aperture |53 -inthe plate |5| provides an entry-way for the 'valve stem, and surroundingthis opening and depending from the plate is the tube ld. Convenientlythe tube |54 may be secured to the plate |5| by welding. Closing thelower end of the tube |56 is the valved inlet member |55 which may beheld in place by means of screws |56. This valved inlet member |55desirably is positioned within the melting pot so that metal will bewithdrawn from a point spaced from the Walls of the Vcontainer and belowany dross which may form on the top of the metal.

Ports |57, conveniently in three walls of the member |55, provide anentrance for molten metal from the melting pot into the passageway |56through the member |55. Flow of molten metal is controlled by means ofthe valve |58 and a cooperating valve seat in the passageway |50 throughthe member |55.

The valve stem |59 extends upwardly through the tube |56 beyond the topof the melting pot. and conveniently may be rotated manually to open andclose the valve. When the valve is open molten metal may pass throughthe ports |57, the passageway |56 in the member |55, and the pipe |60into the tube d. Conveniently the pipe |66 is interiorly shouldered, andthe end oi the pipe 62 slides into the pipe |66 against this shoulder.The pipe 62 passes upwardly through a stulng box |63 in the plate |5l,and thence to the extrusion press in the manner shown in Fig. l.

During the extrusion operation the valve in the lower end of the pressram is closed, and the valve |58 in the melting pot also is closed.` Asthe press cylinder moves away from the ram after the charge in the presscylinder has been extruded, the valve |56 is opened. As hereinbeforedescribed the press cylinder is evacuated throughout this operation, asby means of the pipe connection 38, and when the valve |56 is openedmolten metal is forced by the atmospherlc pressure from the melting potthrough the pipe 62 into the press cylinder.

In extrusion presses Where it is not possible to see the level of lmetalinthe press cylinder during a charging operation, as for example wherethe arrangement shown in Fig. 9 is used for controlling the flow ofmolten metal into the press cylinder, it is desirable to have acontinuously operating indicator to indicate the amount of metalextruded from the press during an extrusion operation, and also theamount of molten metal supplied to the press during a charg-` ingoperation.

The windlass il@ is mounted so as to turn freely about Aa stud |76secured at one end in the support |77.

Secured to the support |77, as at |76, and in front of the windlass|`||l is a dial |79. This dial is shown in front elevation in Fig. 11.The hub of the windlass i7@ Aprojects through the central opening in thedial |79 and has secured thereto the hand |80. It will be apparent thatasthe press cylinder moves up or down the eX- tent of this movement willbe indicated on the dial |79 by means of the hand |80.

Within the melting pot is a iloat |8| which moves up and down as thelevel of molten metal in the pot varies. Conveniently this float may beguided in its movement by the vertically extending arm passing upwardlythrough the top oi the melting pot and engaging the guides |82 and |63fastened to the melting pot.

Secured tol the float guide,` as at |85, is one end of a wire or cable|86. The wire |36 passes upwardly, changes direction around the sheaves|87 and |88, and then passes downwardly and is -secured at its end toone end of a gear rack |89. Fastened to the lower end of the'gear rackis a counterweight |95. Engaging the rack |86 is a pinion |96, rigidlysecured on one end of the shaft |||I passing vthrough the stud |76 tothe face of the dial |79.

Secured to the end of the shaft itl adjacent the dial face is a hand|62. Desirably this hand is secured to the shaft ,HQI so that normallyit will turn with the shaft, but so that it may readily be adjustedrelative to the shaft. Such a connection may comprise the screw |93 inthe end of the shaft, and a helical spring |6| compressed between thehead of the screw and the hand |92. It will be apparent from theforegoing description that any variation in the level of the moltenmetal in the melting pot will be indicated on the dial face by means ofthe hand Deslrably the scale on the dial |76 and the diameter of thewindlass |74 are chosen so that the hand |66 records directly thevertical movement of the press cylinder in inches. The diameter of thepinion |96 desirably is chosen so that the drop in the level of moltenmetal in the melting pot while the cylinder is being charged with moltenmetal will be indicated by/ the hand |92 directly in terms of the numberof inches which the level of metal in the press cylinder is raised. Withthis arrangement the amount of metal extruded during an extrusionoperation is continuously indicated, as is also the amount of metaladded to the press during a charging operation.

The time required for recharging the press may be reduced by permittingmolten metal to enter the press as the press cylinder recedes from theram. During this operation a clearance, usuallyabout one inch in leadpresses, desirably is maintained between the end of the ram and thelevel of the molten metal, and this clearance may be accurately andconveniently controlled with the mechanism described.

For example, when the press cylinder has reached the top of its stroke,that is at the end of the extrusion operation, 'the hand |92 is set oneinch ahead oi the hand |80, for example as shown in Fig. 1l. When thepress cylinderrecedes one inch, the valve in the melting pot beingclosed, the hand |60 has been moved until it is directly under the hand|92. At this point the inlt valve within the melting pot is opened topermit molten metal to flow through the pipe 62 into the press cylinder.The amount by which this valve is opened is adjusted so that as the hand|80 continues to move around the dial, the hand |92 is' kept directlyover the hand |80. With this arrangement the'molten metal will follow upthe receding ram in the press cylinder and maintain the desiredclearance between the end of the ram and the molten metal.

Applicant has provided improved apparatus whereby metal sheaths may beextruded about electrical cables, and in which oxidation of the metalduring the extruding operation is prevented. Splashing of the metal andformation of gas pockets in the charge are greatly reduced. Furthermore,introduction of impurities into the metal during the press chargingoperation is prevented, and the time required between extrudingoperations for charging the press is substantially shortened. Thiseconomyin time is made possible by progressively charging the presscylinder with molten metal as the cylinder and ram separate, and also byaccurately controlling the temperature of the molten metal as it entersthe cylinder.

It will be understood that the present invention may be variouslymodified and embodied within the scope of the subjoined claims.

I claim:

1. In apparatus for 4extruding solidified metal the combination of acylinder, a die block connected to one end of said cylinder, said dieblock -having a transverse die opening therein, a ram air into thecylinder around the ram while per-y mitting relative movementtherebetween, means for charging the cylinder with molten metal throughthe longitudinal opening in the ram, and means for causing relativemovement between the cylinder and the ram to extrude the metal from thecylinder after it has solidied.

2. In apparatus for extruding solidified metal the combination of acylinder, a die block connected to one end of said cylinder, said dieblock having a transverse die opening therein, a ram having an openingextending longitudinally therethrough, said ram extending into the otherend of said cylinder, sealing means betweenV the cylinder and the rampreventing the entrance of air into the cylinder around the ram whilepermitting relative movement therebetween, means for charging thecylinder with molten metal through the longitudinal opening in the ram,means for causing relative movement between the cylinder and the ram toextrude the metal from the ycylinder after it has solidied, and a valvemounted in the inner end of said ram preventing ow of molten metaloutwardly from the cylinder through the longitudinal opening I in theram.

means for causing relative movement between the cylinder and the ram toextrude the metal from the cylinder after it has solidified, a valve insaid openingadjacent the lower end of the ram, and means which, duringthe course of normal operation, causes said valve to open automaticallyin response to movement of the cylinder relative to the ram in onedirection and to close automatically in response to movement of thecylinder relative to the ram in the opposite direction.

4. In apparatus for extruding solidified metal the combination of acylinder, a die block connected to one end of said cylinder, said dieblock having a transverse die opening therein, a ram having an openingextending longitudinally therethrough, said ram extending into the otherend of said cylinder, means for causing relative movement between thecylinder and the ram, sealing means between the cylinder and therampreventing the entrance of air into the cylinder around the ram whilepermitting relative movethe combination of a cylinder, a die block conlnected to one end oi said cylinder, said die block having a transversedie opening therein, a ram having an opening extending longitudinallytherethrough, said ram extending into the other end of said cylinder,means for causing relative movement between the cylinder and the ram,

sealing means between the cylinder and the ram preventing the entranceof air into the cylinder around the ram while permitting relativemovement therebetween? means for progressively charging the cylinderwith molten metal through the longitudinal opening in the ram as the rammoves outwardly relative to the cylinder, and.

means which in the normal course of operation \controls the ow of moltenmetal into the cylinder automatically in response to relative movementbetween the cylinder and the ram.

6. In apparatus for extrudingsolidied metal the combination of acylinder, a die block ccnnected to one end of said cylinder, a ram hav-,f

ing an opening extending longitudinally therethrough, said ram extendinginto the other end of said cylinder, sealing means between the cylinderand the ram preventing the entrance of air into the cylinder around theram while permitting relative movement therebetween, means for chargingthe cylinder with molten metal through the longitudinal opening in theram, means for causing relative movement between the cylinder and theram to extrude the metal from the cylinder after it has solidied, meansfor measuring and indicating continuously the amount of metal extrudedduring an extrusion operation, and meansv for measuring andindicating'continuously the amount of metal which enters the cylinderduring a charging operation.

'1. In apparatus for extrudlng solidified metal the combination of acylinder, a die block connected to one end of said cylinder, a ramhaving an opening extending longitudinally therethrough. said ramextending `into the other end of said cylinder, sealing means betweenthe cylinder and the ram preventing the entrance of air into thecylinder around the ram While permitting .relative movementtherebetween, a container for molten metal, means for charging thecylinder with molten metal from said container through the longitudinalopening in the ram, means for causing relative movement between thecylinder and the ram to extrude the metal from the cylinder after it hassolidified, and means operating automatically and continuously inresponse to extrusion of metal from the cylinder for measuring od andsegregrating an equivalent charge of molten metal for the cylinder.

8. in a metal extruding apparatus the combination of a cylinder, a dieblock connected to one end or" said cylinder, a ram having an openingextending longitudinally therethrough, said ram extending into the otherend of said cylinder, sealing means between the cylinder and the rampreventing the entrance of air into the cylinder around the ram whilepermitting relative movement therebetween, a container for molten metal,means for charging the cylinder with molten metal from said containerthrough the longitudinal opening in the ram, means for causing relativemovement between the cylinder and the ram to extrude metal from thecylinder, means operating automatically in response to relative movementbetween the cylinder and the ram duringextrusion of metal from thecylinder for measuring o and segregating in said container an equivalentcharge of molten metal for the cylinder and operating automatically inresponse to relative movement between the cylinder and the ram in thedirection opposite to that for extruding metal for delivering saidcharge of molten metal to the cylinder.

19. In apparatus for extruding solidied metal the combination of acylinder, a. die block lconnected to one end of said cylinder, a ramextending into the other end of said cylinder, means for charging thecylinder with moltenv metal, means for causingv relative movementbetween the cylinder and the ram to ex'trude the metal from the cylinderafter it has solidied, means for measuring and indicating continuouslythe amount of metalextruded during an extrusion operation, and means formeasuring and indicating continuously the amount of metal which entersthe cylinder during a charging operation.

10. In a metal extruding apparatus the combination of a cylinder, a dieblock connected to one end of said cylinder, a ram extending into theother end of said cylinder, a container for molten metal, means forcharging the cylinder with molten metal from said container, means forcausing relative movement between the cylinder and the ram to extrudemetal from the cylinder, and means operating automatically in responseto relative movement between the cylinder and the ram during theextrusion of metal from the cylinder for measuring oil and segregatingan equivalent charge of molten metal for the cylinder.

11. In a metal extruding apparatus the combination of a cylinder, a dieblock connected to one end of said cylinder, a ram extending into theother end of said cylinder, a container for molten metal, means forcharging the cylinder with molten metal from said container, means forcausing relative movement between the cylinder and the ram to extrudemetal from the cylinder, means operating automatically in response torelative movement between the cylinder and the ram during extrusion ofmetal from the cylinder for measuring o and segregating in saidcontainer an equivalent charge of molten metal for the cylinder andoperating automatically in response to relative movement between thecylinder and the ram in the direction opposite to that for extrudingmetal for delivering said charge of molten metal to the cylinder.

12. In apparatus for extruding solidified metal the combination of acylinder, a die block connected to one end of said cylinder, a tarnextending into the other end of said cylinder, sealing means between thecylinder and the ram preventing the entrance of air into the cylinderaround the ram while permitting relative movement therebetween, meansfor charging the cylinder with molten metal through a longitudinalopening in the ram, means for causing relative movement between thecylinder and the ram to extrudethe metal from the cylinder after it hassolidified, and means for evacuating the space between the cylinder andthe ram under the said sealing means.

13. In apparatus for extruding solidied metal the combination of acylinder, a die block connected to one end of said cylinder, a ramextending into the other end of said cylinder, sealing means between thecylinder andthe ram preventing the .entrance of air into the cylinderaround the ram while permitting relative movement therebetween, meansfor causing relative movement between the cylinder and the ram toextrude the metal from the cylinder after it has solidied, and means formeasuring and indicating continuously the amount of metal extruded vfromthe cylinder during an extrusion operation.

14. In apparatus for extruding solidified metal the combination of acylinder, a die block conlil nected to one end of said cylinder, a ramhavingbination of a cylinder, a die block connected to one end of saidcylinder, a ram having an opening extending longitudinally therethrough,said ram extending into'the other end of said cylinder, means forcausing relativemovement between the cylinder and the ram, means forcharging the cylinder with molten metal through the longitudinal openingin the ram, said means comprising a metal pipe smaller than thelongitudinal opening through the ram extending from the inner end of theram outwardly through the longitudinal opening therein, and means forevacuating the space in said opening exteriorly of said pipe.

16. In a metal extruding apparatus the combination of la cylinder, a dieblock connected to one end of said cylinder, a. ram having an openingextending longitudinally therethrough, said ram extending into the otherend of said cylinder, means for causing relative movement between thecylinder and the ram, means for charging the cylinder with molten metalthrough the longitudinal opening in the ram, said means comprising ametal pipe extending from the inner end of the ram outwardly through thelongitudinal opening therein, and means for heating said pipeelectrically throughout its length.

17. In a metal extruding apparatus the combination of a cylinder, a dieblock connected to one end of said cylinder, a ram havingan openingextending longitudinally therethrough,v said ram extending into theother end of said cylinder,

means for causing relative movement between the cylinder and the ram',means for charging the cylinder with molteny metal through thelongitudinal opening in the ram, said means com. prising axnetal pipeextending from the inner end of the ram outwardly through' thelongitudinal opening therein, and an electrical connection between thepipe and the ram adjacent the inner end of the ram, said pipe and rambeing otherwise insulated electrically one from the other.

18. The combination with a press for extruding a metal sheath on anelectrical cable, said press comprising a cylinder, a die blockconnected to one end of said cylinder, a ram having an openinglongitudinally therethrough extending into the other end of thecylinder, and means for causing relative movement between the cylinder land the ram, of a container for the molten metal with which the press isto becharged, and means for charging the press With'molten metal fromthe container, said means comprising a continuous one-piece pipeextending from a point, in the container below the level of the metaland spaced from the walls of the container through the longitudinalopening in the ram to a point Y where it discharges directly into thepress cylinder.

19. The combination with a press for extruding solidified metal, saidpress comprising a cylinder, a die block connected to one end of saidgitudinal opening in the ram to a point where it discharges directlyinto the press, and means for passing an electric current longitudinallythrough the pipe to maintain the pipe temperature sufflciently high toprevent the molten metal from congealing while flowing through the pipe.

20. The combination with a press for extruding solidiiled metal ofacontainer for the molten metal with which the press is to be charged,and means operating automatically and continuously in response toextrusion o'f metal from the press to segregate an equivalent quantityof molten metal in the container.

2l. The method of operating apparatus for extruding metal sheaths onelectrical cables, said apparatus comprising a cylinder, die block andram, which method comprises electing relative withdrawal movementbetween the cylinder and the ram to permit charging of the cylinder withmolten metal, discontinuing such movement while the cylinder stillengages the end of the ram, charging the cylinder with molten metal freefrom gas and other impurities, permitting the molten metal to cool andsolidify,` applying suction to the top of the metal in the cylinder toremove from the cylinder during the charging and cooling operations anygas which may have been entrained in the molten metal, and effectingrelative movement between the cylinder and the ram to extrude thesolidified metal through the die block.

22. 'I'he method of charging the cylinder of a press for extruding metalsheaths on electrical cables with molten metal from a molten metalcontainer, which method comprises withdrawing molten metal from thecontainer at a point below the dross line and spaced from the walls ofthe container, conveying the" metal so withdrawn to the press andcharging the press cylinder therewith, preventing access of air to themolten metal in its passage from the container to the press cylinder,and applying suction around the ram and in the upper portion of thecylinder to remove from the cylinder during the charging operation anygas which may have been entrained in the'molten metal.

EDGAR, W. MAcKNIGHT.

